To reduce automobile accidents and improve automobile safety, a safety system technology for detecting an obstacle and avoiding the obstacle or notifying a driver thereof is important. Furthermore, to reduce a load on the driver and obtain further safety, an autonomous travelling technology for recognizing a shape of unevenness, a bump, and the like of a road surface and for detecting travelable region is demanded.
On the other hand, cost reduction has always been strongly demanded of an automobile, and the cost reduction is an important issue for a safety system as well. In the object recognition device mounted on the automobile, a range finder such as a light detection and ranging (LIDAR) (laser radar) and a millimeter wave radar is used; however, to achieve the cost reduction of the device, it is necessary that the system is constituted of an inexpensive radar.
Since the inexpensive radar has a few scan lines and a rather low angular resolution, there is a large interval between scan positions (measurement points), whereby it is possible to obtain distance data for discrete positions only. Thus, object recognition and position detection are difficult by using the radar only. Therefore, a common system is combined with a camera to perform the object recognition and the position detection based on an image from the camera.
For example, PTL 1 discloses a method for calculating a distance to an obstacle by using, among distance data measured by the radar, the distance data existing within a rectangle region containing the obstacle detected in the image from the camera.